Novel vaccines against multiple subtypes of influenza virus

ABSTRACT

An aspect of the present invention is directed towards DNA plasmid vaccines capable of generating in a mammal an immune response against a plurality of influenza virus subtypes, comprising a DNA plasmid and a pharmaceutically acceptable excipient. The DNA plasmid is capable of expressing a consensus influenza antigen in a cell of the mammal in a quantity effective to elicit an immune response in the mammal, wherein the consensus influenza antigen comprises consensus hemagglutinin (HA), neuraminidase (NA), matrix protein, nucleoprotein, M2 ectodomain-nucleo-protein (M2e-NP), or a combination thereof. Preferably the consensus influenza antigen comprises HA, NA, M2e-NP, or a combination thereof. The DNA plasmid comprises a promoter operably linked to a coding sequence that encodes the consensus influenza antigen. Additionally, an aspect of the present invention includes methods of eliciting an immune response against a plurality of influenza virus subtypes in a mammal using the DNA plasmid vaccines provided.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 60/987,284, filed Nov. 12, 1997, the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to improved influenza vaccines, improved methods for inducing immune responses, and for prophylactically and/or therapeutically immunizing individuals against influenza.

BACKGROUND

The use of nucleic acid sequences to vaccinate against animal and human diseases has been studied. Studies have focused on effective and efficient means of delivery in order to yield necessary expression of the desired antigens, resulting immunogenic response and ultimately the success of this technique. One method for delivering nucleic acid sequences such as plasmid DNA is the electroporation (EP) technique. The technique has been used in human clinical trials to deliver anti-cancer drugs, such as bleomycin, and in many preclinical studies on a large number of animal species.

The influenza virus genome is contained on eight single (non-paired) RNA strands that code for eleven proteins (HA, NA, NP, M1, M2, NS1, NEP, PA, PB1, PB1-F2, PB2). The segmented nature of the genome allows for the exchange of entire genes between different viral strains during cellular cohabitation. The eight RNA segments are: HA, which encodes hemagglutinin (about 500 molecules of hemagglutinin are needed to make one virion); NA, which encodes neuraminidase (about 100 molecules of neuraminidase are needed to make one virion); NP, which encodes nucleoprotein; M, which encodes two matrix proteins (the M1 and the M2) by using different reading frames from the same RNA segment (about 3000 matrix protein molecules are needed to make one virion); NS, which encodes two distinct non-structural proteins (NS1 and NEP) by using different reading frames from the same RNA segment; PA, which encodes an RNA polymerase; PB1, which encodes an RNA polymerase and PB1-F2 protein (induces apoptosis) by using different reading frames from the same RNA segment; and PB2, which encodes an RNA polymerase.

Influenza hemagglutinin (HA) is expressed on the surface of influenza viral particles and is responsible for initial contact between the virus and its host cell. HA is a well-known immunogen. Influenza A strain H5N1, an avian influenza strain, particularly threatens the human population because of its HA protein (H5) which, if slightly genetically reasserted by natural mutation, has greatly increased infectivity of human cells as compared to other strains of the virus. Infection of infants and older or immunocompromised adult humans with the viral H5N1 strain is often correlated to poor clinical outcome. Therefore, protection against the H5N1 strain of influenza is a great need for the public.

There are two classes of anti-influenza agents available, inhibitors of influenza A cell entry/uncoating (such as antivirals amantadine and rimantadine) and neuraminidase inhibitors (such as antivirals oseltamivir, zanamivir). These antiviral agents inhibit the cellular release of both influenza A and B. Concerns over the use of these agents have been reported due to findings of strains of virus resistant to these agents.

Influenza vaccines are a popular seasonal vaccine and many people have experienced such vaccinations. However, the vaccinations are limited in their protective results because the vaccines are specific for certain subtypes of virus. The Centers for Disease Control and Prevention promote vaccination with a “flu shot” that is a vaccine that contains three influenza viruses (killed viruses): one A (H3N2) virus, one A (H1N1) virus, and one B virus. They also report that the viruses in the vaccine change each year based on international surveillance and scientists' estimations about which types and strains of viruses will circulate in a given year. Thus, it is apparent that vaccinations are limited to predictions of subtypes, and the availability of a specific vaccine to that subtype.

There still remains a need for effective influenza vaccines that are economical and effective across numerous subtypes. Further, there remains a need for an effective method of administering DNA vaccines to a mammal in order to provide immunization against influenza either prophylatically or therapeutically.

SUMMARY OF THE INVENTION

One aspect of the present invention relates to a DNA plasmid vaccine capable of generating in a mammal an immune response against a plurality of influenza virus subtypes, comprising a DNA plasmid and a pharmaceutically acceptable excipient. The DNA plasmid is capable of expressing a consensus influenza antigen in a cell of the mammal in a quantity effective to elicit an immune response in the mammal, wherein the consensus influenza antigen comprises consensus hemagglutinin (HA), neuraminidase (NA), matrix protein, nucleoprotein, M2 ectodomain-nucleo-protein (M2e-NP), or a combination thereof. Preferably the consensus influenza antigen comprises HA, NA, M2e-NP, or a combination thereof. The DNA plasmid comprises a promoter operably linked to a coding sequence that encodes the consensus influenza antigen. Preferably, the DNA plasmid vaccine is one having a concentration of total DNA plasmid of 1 mg/ml or greater.

Another aspect of the present invention relates to DNA plasmids capable of expressing a consensus influenza antigen in a cell of the mammal, the consensus influenza antigen comprising consensus hemagglutinin (HA), neuraminidase (NA), matrix protein, nucleoprotein, M2 ectodomain-nucleo-protein (M2e-NP), or a combination thereof. Preferably the consensus influenza antigen comprises HA, NA, M2e-NP, or a combination thereof. The DNA plasmid comprises a promoter operably linked to a coding sequence that encodes the consensus influenza antigen.

Another aspect of the present invention relates to methods of eliciting an immune response against a plurality of influenza virus subtypes in a mammal. The methods include delivering a DNA plasmid vaccine to tissue of the mammal, the DNA plasmid vaccine comprising a DNA plasmid capable of expressing a consensus influenza antigen in a cell of the mammal to elicit an immune response in the mammal, the consensus influenza antigen comprising consensus HA, NA, M2e-NP or a combination thereof, and electroporating cells of the tissue with a pulse of energy at a constant current effective to permit entry of the DNA plasmids in the cells.

BRIEF DESCRIPTION OF THE DRAWINGS

The numerous objects and advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying figures, in which:

FIG. 1 displays a schematic representation (plasmid maps) of the DNA plasmid constructs used in the studies described herein. Consensus HA, NA and M2e-NP constructs were generated by analyzing primary virus sequences from 16 H5 viruses that have proven fatal to humans in recent years, and over 40 human N1 viruses (Los Alamos National Laboratory's Influenza Sequence Database). After generating the consensus sequences, the constructs were optimized for mammalian expression, including the addition of a Kozak sequence, codon optimization, and RNA optimization. These constructs were then subcloned into the pVAX vector (Invitrogen, Carlsbad, Calif.). Plasmids pGX2001 (consensus HA), pGX2002 (consensus NA), pGX2003 (consensus M2e-NP) are shown. The plasmid pCMVSEAP, displayed, encodes the reporter protein secreted embryonic alkaline phosphatase (SEAP).

FIG. 2 displays a bar graph of the results of the HI titers in pig serum at Day 35 post-injection. The highest titers were found in the group administered 2 mg of HA-expressing plasmid at a current setting of 0.5 A (120±40; *P=0.11 versus 2 mg/0.3 A and *P=0.02 versus 2 mg/0.1 A). The three groups administered descending doses of plasmid and electroporated at 0.5 A also demonstrated decreasing HI titers.

FIG. 3 displays a bar graph of the IFN-γ ELISpot counts. The counts were highest in pigs administered 2 mg of HA and 2 mg of NA plasmid vaccine (for a total of 4 mg plasmid) and electroporated with 0.3 A of current (2000 spots) and in the group administered 0.8 mg of HA and 0.8 mg of NA plasmid vaccine (for a total of 1.6 mg plasmid) electroporated with 0.5 A of current (934 spots). For comparison purposes, the cellular immune responses of an unimmunized control group are depicted.

FIGS. 4A and 4B display bar graphs showing results from muscle biopsies from treated pigs at Day 14 and Day 35: FIG. 4A displays a bar graph showing the mean pathology scores for all groups. FIG. 4B displays a bar graph showing the muscle necrosis and fibrosis scores. The group injected with 6 mg total plasmid and electroporated at 0.5 A exhibited the highest mean pathology score (*P<0.0002 as compared to controls). The pathology scores were significantly reduced by Day 35 compared to Day 14 in all groups (P<0.05) except for the 0.3 mg/0.3 A group (P=0.057) and 2.4 mg/0.1 A group (P=1.0).

FIG. 5 displays the percent change in weight of ferrets after challenge with H5N1 virus (A/Viet/1203/2004(H5N1)/PR8-IBCDC-RG). Ferrets that were vaccinated with HA, HA+M2e-NP or HA+M2e-NP+NA lost significantly less weight than control animals (*P<0.005 versus controls) in the 9 days post-challenge period. One animal in the HA vaccine group actually gained weight post-challenge.

FIG. 6 displays a graph showing the body temperatures of ferrets during the 9 days post-challenge. Control animals showed higher body temperatures than the vaccinated animals. The body temperature on day 5 is not depicted as it was measured at a different time of day and all the temperatures regardless of group were lower.

FIG. 7 displays a bar graph of results from HI titers in ferrets after vaccination; the assay was performed using reassortant viruses obtained from the Center for Disease Control: A/Viet/1203/04 or Indo/05/2005 influenza strains.

FIG. 8 displays a bar graph of results from HI titers measured three weeks after the second immunization. Macaques immunized ID followed by EP showed significantly higher HI titers than all other groups (P<0.03). Non-treated controls did not exhibit any HI titers.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The following abbreviated, or shortened, definitions are given to help the understanding of the preferred embodiments of the present invention. The abbreviated definitions given here are by no means exhaustive nor are they contradictory to the definitions as understood in the field or dictionary meaning. The abbreviated definitions are given here to supplement or more clearly define the definitions known in the art.

DEFINITIONS

Sequence homology for nucleotides and amino acids as used herein may be determined using FASTA, BLAST and Gapped BLAST (Altschul et al., Nuc. Acids Res., 1997, 25, 3389, which is incorporated herein by reference in its entirety) and PAUP* 4.0b10 software (D. L. Swofford, Sinauer Associates, Massachusetts). Briefly, the BLAST algorithm, which stands for Basic Local Alignment Search Tool is suitable for determining sequence similarity (Altschul et al., J. Mol. Biol., 1990, 215, 403-410, which is incorporated herein by reference in its entirety). Software for performing BLAST analyses is publicly available through the National Center for Biotechnology Information (http://www.ncbi.nlm.nih.gov). One measure of similarity provided by the BLAST algorithm is the smallest sum probability (P(N)), which provides an indication of the probability by which a match between two nucleotide sequences would occur by chance. For example, a nucleic acid is considered similar to another if the smallest sum probability in comparison of the test nucleic acid to the other nucleic acid is less than about 1, preferably less than about 0.1, more preferably less than about 0.01, and most preferably less than about 0.001. “Percentage of similarity” can be calculated using PAUP* 4.0b10 software (D. L. Swofford, Sinauer Associates, Massachusetts). The average similarity of the consensus sequence is calculated compared to all sequences in the phylogenic tree.

As used herein, the term “genetic construct” or “nucleic acid construct” is used interchangeably and refers to the DNA or RNA molecules that comprise a nucleotide sequence which encodes protein. The coding sequence, or “encoding nucleic acid sequence,” includes initiation and termination signals operably linked to regulatory elements including a promoter and polyadenylation signal capable of directing expression in the cells of the individual to whom the nucleic acid molecule is administered.

As used herein, the term “expressible form” refers to nucleic acid constructs that contain the necessary regulatory elements operable linked to a coding sequence that encodes a protein such that when present in the cell of the individual, the coding sequence will be expressed.

The term “constant current” is used herein to define a current that is received or experienced by a tissue, or cells defining said tissue, over the duration of an electrical pulse delivered to same tissue. The electrical pulse is delivered from the electroporation devices described herein. This current remains at a constant amperage in said tissue over the life of an electrical pulse because the electroporation device provided herein has a feedback element, preferably having instantaneous feedback. The feedback element can measure the resistance of the tissue (or cells) throughout the duration of the pulse and cause the electroporation device to alter its electrical energy output (e.g., increase voltage) so current in same tissue remains constant throughout the electrical pulse (on the order of microseconds), and from pulse to pulse. In some embodiments, the feedback element comprises a controller.

The term “feedback” or “current feedback” is used interchangeably and means the active response of the provided electroporation devices, which comprises measuring the current in tissue between electrodes and altering the energy output delivered by the EP device accordingly in order to maintain the current at a constant level. This constant level is preset by a user prior to initiation of a pulse sequence or electrical treatment. Preferably, the feedback is accomplished by the electroporation component, e.g., controller, of the electroporation device, as the electrical circuit therein is able to continuously monitor the current in tissue between electrodes and compare that monitored current (or current within tissue) to a preset current and continuously make energy-output adjustments to maintain the monitored current at preset levels. In some embodiments, the feedback loop is instantaneous as it is an analog closed-loop feedback.

The terms “electroporation,” “electro-permeabilization,” or “electro-kinetic enhancement” (“EP”) as used interchangeably herein refer to the use of a transmembrane electric field pulse to induce microscopic pathways (pores) in a bio-membrane; their presence allows biomolecules such as plasmids, oligonucleotides, siRNA, drugs, ions, and water to pass from one side of the cellular membrane to the other.

The term “decentralized current” is used herein to define the pattern of electrical currents delivered from the various needle electrode arrays of the electroporation devices described herein, wherein the patterns minimize, or preferably eliminate, the occurrence of electroporation related heat stress on any area of tissue being electroporated.

The term “feedback mechanism” as used herein refers to a process performed by either software or hardware (or firmware), which process receives and compares the impedance of the desired tissue (before, during, and/or after the delivery of pulse of energy) with a present value, preferably current, and adjusts the pulse of energy delivered to achieve the preset value. The term “impedance” is used herein when discussing the feedback mechanism and can be converted to a current value according to Ohm's law, thus enabling comparisons with the preset current. In a preferred embodiment, the “feedback mechanism” is performed by an analog closed loop circuit.

The term “immune response” is used herein to mean the activation of a host's immune system, e.g., that of a mammal, in response to the introduction of influenza consensus antigen via the provided DNA plasmid vaccines. The immune response can be in the form of a cellular or humoral response, or both.

The term “consensus” or “consensus sequence” is used herein to mean a synthetic nucleic acid sequence, or corresponding polypeptide sequence, constructed based on analysis of an alignment of multiple subtypes of a particular influenza antigen, that can be used to induce broad immunity against multiple subtypes or serotypes of a particular influenza antigen. Consensus influenza antigens include HA, including consensus H1, H2, H3, or H5, NA, NP, matrix protein, and nonstructural protein. Also, synthetic antigens such as fusion proteins, e.g., M2e-NP, can be manipulated to consensus sequences (or consensus antigens).

The term “adjuvant” is used herein to mean any molecule added to the DNA plasmid vaccines described herein to enhance antigenicity of the influenza antigen encoded by the DNA plasmids and encoding nucleic acid sequences described hereinafter.

The term “subtype” or “serotype” is used herein interchangeably and in reference to influenza viruses, and means genetic variants of an influenza virus antigen such that one subtype is recognized by an immune system apart from a different subtype (or, in other words, each subtype is different in antigenic character from a different subtype).

In some embodiments, there are DNA plasmids capable of expressing a consensus influenza antigen in a cell of the mammal, the consensus influenza antigen comprising consensus hemagglutinin (HA), neuraminidase (NA), matrix protein, nucleoprotein, M2 ectodomain-nucleo-protein (M2e-NP), or a combination thereof. Preferably the consensus influenza antigen comprises HA, NA, M2e-NP, or a combination thereof. The DNA plasmid comprises a promoter operably linked to a coding sequence that encodes the consensus influenza antigen.

In some embodiments, the present invention provides DNA plasmid vaccines that are capable of generating in a mammal an immune response against a plurality of influenza virus subtypes, the DNA plasmid vaccines comprising a DNA plasmid and a pharmaceutically acceptable excipient. The DNA plasmid is capable of expressing a consensus influenza antigen in a cell of the mammal in a quantity effective to elicit an immune response in the mammal, wherein the consensus influenza antigen comprises consensus hemagglutinin (HA), neuraminidase (NA), matrix protein, nucleoprotein, M2 ectodomain-nucleo-protein (M2e-NP), or a combination thereof. Preferably the consensus influenza antigen comprises HA, NA, M2e-NP, or a combination thereof. The DNA plasmid comprises a promoter operably linked to a coding sequence that encodes the consensus influenza antigen. In some embodiments, the DNA plasmid vaccine is one having a concentration of total DNA plasmid of 1 mg/ml or greater. The immune response can be a cellular or humoral response, or both; preferably, the immune response is both cellular and humoral.

In some embodiments, the DNA plasmid can further include an IgG leader sequence attached to an N-terminal end of the coding sequence and operably linked to the promoter. In addition, in some embodiments, the DNA plasmid can further include a polyadenylation sequence attached to the C-terminal end of the coding sequence. In some embodiments, the DNA plasmid is codon optimized.

In some embodiments of the present invention, the DNA plasmid vaccines can further include an adjuvant. In some embodiments, the adjuvant is selected from the group consisting of: alpha-interferon, gamma-interferon, platelet derived growth factor (PDGF), TNFα, TNFβ, GM-CSF, epidermal growth factor (EGF), cutaneous T cell-attracting chemokine (CTACK), epithelial thymus-expressed chemokine (TECK), mucosae-associated epithelial chemokine (MEC), IL-12, IL-15, MHC, CD80, CD86 including IL-15 having the signal sequence deleted and optionally including the signal peptide from IgE. Other genes which may be useful adjuvants include those encoding: MCP-1, MIP-1α, MIP-1p, IL-8, RANTES, L-selectin, P-selectin, E-selectin, CD34, GlyCAM-1, MadCAM-1, LFA-1, VLA-1, Mac-1, pl50.95, PECAM, ICAM-1, ICAM-2, ICAM-3, CD2, LFA-3, M-CSF, G-CSF, IL-4, mutant forms of IL-18, CD40, CD40L, vascular growth factor, fibroblast growth factor, IL-7, nerve growth factor, vascular endothelial growth factor, Fas, TNF receptor, Flt, Apo-1, p55, WSL-1, DR3, TRAMP, Apo-3, AIR, LARD, NGRF, DR4, DR5, KILLER, TRAIL-R2, TRICK2, DR6, Caspase ICE, Fos, c-jun, Sp-1, Ap-1, Ap-2, p38, p65Rel, MyD88, IRAK, TRAF6, IkB, Inactive NIK, SAP K, SAP-1, JNK, interferon response genes, NFkB, Bax, TRAIL, TRAILrec, TRAILrecDRC5, TRAIL-R3, TRAIL-R4, RANK, RANK LIGAND, Ox40, Ox40 LIGAND, NKG2D, MICA, MICB, NKG2A, NKG2B, NKG2C, NKG2E, NKG2F, TAP1, TAP2 and functional fragments thereof. In some preferred embodiments, the adjuvant is selected from IL-12, IL-15, CTACK, TECK, or MEC.

In some embodiments, the pharmaceutically acceptable excipient is a transfection facilitating agent, which can include the following: surface active agents, such as immune-stimulating complexes (ISCOMS), Freunds incomplete adjuvant, LPS analog including monophosphoryl lipid A, muramyl peptides, quinone analogs, vesicles such as squalene and squalene, hyaluronic acid, lipids, liposomes, calcium ions, viral proteins, polyanions, polycations, or nanoparticles, or other known transfection facilitating agents. Preferably, the transfection facilitating agent is a polyanion, polycation, including poly-L-glutamate (LGS), or lipid. Preferably, the transfection facilitating agent is poly-L-glutamate, and more preferably, the poly-L-glutamate is present in the DNA plasmid vaccine at a concentration less than 6 mg/ml. In some embodiments, the concentration of poly-L-glutamate in the DNA plasmid vaccine is less than 4 mg/ml, less than 2 mg/ml, less than 1 mg/ml, less than 0.750 mg/ml, less than 0.500 mg/ml, less than 0.250 mg/ml, less than 0.100 mg/ml, less than 0.050 mg/ml, or less than 0.010 mg/ml.

In some embodiments, the DNA plasmid vaccine can include a plurality of different DNA plasmids. In some examples, the different DNA plasmids include a DNA plasmid comprising a nucleic acid sequence that encodes a consensus HA, a DNA plasmid comprising a sequence that encodes a consensus NA, and a DNA plasmid comprising a sequence that encodes a consensus M2e-NP. In some embodiments, the consensus HA is a consensus H1, consensus H2, consensus H3, or consensus H5. Preferably, the consensus HA is nucleotide sequence that is SEQ ID NO:1 (H5N1 HA consensus DNA), SEQ ID NO:9 (consensus H1 DNA), SEQ ID NO: 11 (consensus H3 DNA), or SEQ ID NO:13 (consensus H5). The consensus HA can also be a nucleotide sequence encoding a polypeptide of the sequence SEQ ID NO: 2, SEQ ID NO: 10, SEQ ID NO: 12, or SEQ ID NO: 14. In some embodiments, the consensus NA is a nucleotide sequence that is SEQ ID NO: 3, or a nucleotide sequence encoding a polypeptide of the sequence SEQ ID NO: 4. In some embodiments, the consensus M2e-NP is a nucleotide sequence that is SEQ ID NO:7, or a nucleotide sequence encoding a polypeptide of the sequence SEQ ID NO:8. In one preferred embodiment, the DNA plasmid vaccine includes a DNA plasmid comprising a sequence that encodes a consensus H1, a DNA plasmid comprising a sequence that encodes a consensus H2, a DNA plasmid comprising a sequence that encodes a consensus H3, a DNA plasmid comprising a sequence that encodes a consensus H5, a DNA plasmid comprising a sequence that encodes a consensus NA, and a DNA plasmid comprising a sequence that encodes a consensus M2e-NP.

In some embodiments, the DNA plasmid vaccine can include a plurality of different DNA plasmids, including at least one DNA plasmid that can express consensus influenza antigens and at least one that can express one influenza subtype antigen. In some examples, the different DNA plasmids that express consensus antigen include a DNA plasmid comprising a nucleic acid sequence that encodes a consensus HA, a DNA plasmid comprising a sequence that encodes a consensus NA, and a DNA plasmid comprising a sequence that encodes a consensus M2e-NP. In some embodiments, the DNA plasmid vaccine comprises a DNA plasmid that can express a consensus HA antigen, e.g., consensus H1, H3 or H5, and a DNA plasmid that can express any one of the following influenza A antigens: H1, H2, H3, H4, H5, H6, H7, H8, H9, H10, H11, H12, H13, H14, H15, H16, N1, N2, N3, N4, N5, N6, N7, N8, N9, NP, M1, M2, NS1, or NEP, or a combination thereof. In some embodiments, the DNA plasmid vaccine comprises a DNA plasmid that can express a consensus NA antigen and a DNA plasmid that can express any one of the following influenza A antigens: H1, H2, H3, H4, H5, H6, H7, H8, H9, H10, H11, H12, H13, H14, H15, H16, N1, N2, N3, N4, N5, N6, N7, N8, N9, NP, M1, M2, NS1, or NEP, or a combination thereof. In some embodiments, the DNA plasmid vaccine comprises a DNA plasmid that can express a consensus M2e-NP and a DNA plasmid that can express any one of the following influenza A antigens: H1, H2, H3, H4, H5, H6, H7, H8, H9, H10, H11, H12, H13, H14, H15, H16, N1, N2, N3, N4, N5, N6, N7, N8, N9, NP, M1, M2, NS1, or NEP, or a combination thereof.

In some embodiments, the DNA plasmid vaccine can be delivered to a mammal to elicit an immune response; preferably the mammal is a primate, including human and nonhuman primate, a cow, pig, chicken, dog, or ferret. More preferably, the mammal is a human primate.

One aspect of the present invention relates to methods of eliciting an immune response against a plurality of influenza virus subtypes in a mammal. The methods include delivering a DNA plasmid vaccine to tissue of the mammal, the DNA plasmid vaccine comprising a DNA plasmid capable of expressing a consensus influenza antigen in a cell of the mammal to elicit an immune response in the mammal, the consensus influenza antigen comprising consensus HA, NA, M2e-NP or a combination thereof, and electroporating cells of the tissue with a pulse of energy at a constant current effective to permit entry of the DNA plasmids in the cells.

In some embodiments, the methods of the present invention include the delivering step, which comprises injecting the DNA plasmid vaccine into intradermic, subcutaneous or muscle tissue. Preferably, these methods include using an in vivo electroporation device to preset a current that is desired to be delivered to the tissue; and electroporating cells of the tissue with a pulse of energy at a constant current that equals the preset current. In some embodiments, the electroporating step further comprises: measuring the impedance in the electroporated cells; adjusting energy level of the pulse of energy relative to the measured impedance to maintain a constant current in the electroporated cells; wherein the measuring and adjusting steps occur within a lifetime of the pulse of energy.

In some embodiments, the electroporating step comprises delivering the pulse of energy to a plurality of electrodes according to a pulse sequence pattern that delivers the pulse of energy in a decentralized pattern.

In some embodiments, the DNA plasmid influenza vaccines of the invention comprise nucleotide sequences that encode a consensus HA, or a consensus HA and a nucleic acid sequence encoding influenza proteins selected from the group consisting of: SEQ ID NOS: 4, 6, and 8. SEQ ID NOS:1 and 13 comprise the nucleic acid sequence that encodes consensus H5N1 HA and H5 of influenza virus, respectively. SEQ ID NOS:2 and 14 comprise the amino acid sequence for H5N1 HA and H5 of influenza virus, respectively. In some embodiments of the invention, the vaccines of the invention comprise SEQ ID NO:3 or SEQ ID NO:4. SEQ ID NO:3 comprises the nucleic acid sequence that encodes influenza H1N1 and H5N1 (H1N1/H5N1) NA consensus sequences. SEQ ID NO:4 comprises the amino acid sequence for influenza H1N1/H5N1 NA consensus sequences. In some embodiments of the invention, the vaccines of the invention comprise SEQ ID NO:5 or SEQ ID NO:6. SEQ ID NO:5 comprises the nucleic acid sequence that encodes influenza H1N1/H5N1 M1 consensus sequences. SEQ ID NO:6 comprises the amino acid sequence for influenza H1N1/H5N1 M1 consensus sequences. In some embodiments of the invention, the vaccines of the invention comprise SEQ ID NO:7 or SEQ ID NO:8. SEQ ID NO:7 comprises the nucleic acid sequence that encodes influenza H5N1 M2E-NP consensus sequence. SEQ ID NO:8 comprises the amino acid sequence for influenza H5N1 M2E-NP consensus sequence. In some embodiments of the invention, the vaccines of the invention comprise SEQ ID NO:9 or SEQ ID NO:10. SEQ ID NO:9 comprises the nucleic acid sequence that encodes influenza H1N1 HA consensus sequences. SEQ ID NO:4 comprises the amino acid sequence for influenza H1N1 HA consensus sequences. In some embodiments of the invention, the vaccines of the invention comprise SEQ ID NO: 11 or SEQ ID NO: 12. SEQ ID NO:11 comprises the nucleic acid sequence that encodes influenza H3N1 HA consensus sequences. SEQ ID NO: 12 comprises the amino acid sequence for influenza H3N1 HA consensus sequences. The consensus sequence for influenza virus strain H5N1 HA includes the immunodominant epitope set forth in SEQ ID NO:1 or SEQ ID NO:13. The influenza virus H5N1 HA amino acid sequence encoded by SEQ ID NO: 1 is SEQ ID NO:2, and that encoded by SEQ ID NO:13 is SEQ ID NO:14. The consensus sequence for influenza virus H1N1/H5N1 NA includes the immunodominant epitope set forth in SEQ ID NO:3. The influenza virus strains H1N1/H5N1 NA amino acid sequence encoded by SEQ ID NO:3 is SEQ ID NO:4. The consensus sequence for influenza virus strains H1N1/H5N1 M1 includes the immunodominant epitope set forth in SEQ ID NO:5. The influenza virus H1N1/H5N1 M1 amino acid sequence encoded by SEQ ID NO:5 is SEQ ID NO:6. The consensus sequence for influenza virus H5N1 M2E-NP includes the immunodominant epitope set forth in SEQ ID NO:7. The influenza virus H5N1 M2E-NP amino acid sequence encoded by SEQ ID NO:7 is SEQ ID NO:8. Vaccines of the present invention may include protein products encoded by the nucleic acid molecules defined above or any fragments of proteins.

The present invention also comprises DNA fragments that encode a polypeptide capable of eliciting an immune response in a mammal substantially similar to that of the non-fragment for at least one influenza subtype. The DNA fragments are fragments selected from at least one of the various encoding nucleotide sequences of the present invention, including SEQ ID NOS:1, 3, 5, 7, 9, 11, and 13, and can be any of the following described DNA fragments, as it applies to the specific encoding nucleic acid sequence provided herein. In some embodiments, DNA fragments can comprise 30 or more, 45 or more, 60 or more, 75 or more, 90 or more, 120 or more, 150 or more, 180 or more, 210 or more, 240 or more, 270 or more, 300 or more, 360 or more, 420 or more, 480 or more, 540 or more, 600 or more, 660 or more, 720 or more, 780 or more, 840 or more, 900 or more, 960 or more, 1020 or more, 1080 or more, 1140 or more, 1200 or more, 1260 or more, 1320 or more, 1380 or more, 1440 or more, 1500 or more, 1560 or more, 1620 or more, 1680 or more, or 1740 or more nucleotides. In some embodiments, DNA fragments can comprise coding sequences for the immunoglobulin E (IgE) leader sequences. In some embodiments, DNA fragments can comprise fewer than 60, fewer than 75, fewer than 90, fewer than 120, fewer than 150, fewer than 180, fewer than 210, fewer than 240, fewer than 270, fewer than 300, fewer than 360, fewer than 420, fewer than 480, fewer than 540, fewer than 600, fewer than 660, fewer than 720, fewer than 780, fewer than 840, fewer than 900, fewer than 960, fewer than 1020, fewer than 1080, fewer than 1140, fewer than 1200, fewer than 1260, fewer than 1320, fewer than 1380, fewer than 1440, fewer than 1500, fewer than 1560, fewer than 1620, fewer than 1680, or fewer than 1740 nucleotides. Preferably, the DNA fragments are fragments of SEQ ID NOS:1, 3, 7, 9, 11 or 13, and more preferably fragments of SEQ ID NOS:1, 5, 9, 11, or 13, and even more preferably fragments of SEQ ID NOS:1, 9, or 13.

The present invention also comprises polypeptide fragments that are capable of eliciting an immune response in a mammal substantially similar to that of the non-fragment for at least one influenza subtype. The polypeptide fragments are selected from at least one of the various polypeptide sequences of the present invention, including SEQ ID NOS:2, 4, 6, 8, 10, 12, and 14, and can be any of the following described polypeptide fragments, as it applies to the specific polypeptide sequence provided herein. In some embodiments, polypeptide fragments can comprise 15 or more, 30 or more, 45 or more, 60 or more, 75 or more, 90 or more, 105 or more, 120 or more, 150 or more, 180 or more, 210 or more, 240 or more, 270 or more, 300 or more, 360 or more, 420 or more, 480 or more, 540 or more, or 565 or more amino acids. In some embodiments, polypeptide fragments can comprise fewer than 30, fewer than 45, fewer than 60, fewer than 75, fewer than 90, fewer than 120, fewer than 150, fewer than 180, fewer than 210, fewer than 240, fewer than 270, fewer than 300, fewer than 360, fewer than 420, fewer than 480, fewer than 540, or fewer than 565 amino acids. Preferably, the polypeptide fragments are fragments of SEQ ID NOS:2, 4, 8, 10, 12, or 14, and more preferably fragments of SEQ ID NOS:2, 6, 10, 12, or 14, and even more preferably fragments of SEQ ID NOS:2, 10, or 14.

The determination of a fragment eliciting an immune response in a mammal substantially similar to that of the non-fragment for at least one influenza subtype can be readily determined by one of ordinary skill. The fragment can be analyzed to contain at least one, preferably more, antigenic epitopes as provided by a publicly available database, such as the Los Alamos National Laboratory's Influenza Sequence Database. In addition, immune response studies can be routinely assessed using mice and HI titers and ELISpots analysis, such as that shown in the Examples below.

According to some embodiments of the invention, methods of inducing or eliciting an immune response in mammals against a plurality of influenza viruses comprise administering to the mammals: a) the influenza strain H5N1 consensus HA protein, functional fragments thereof, or expressible coding sequences thereof; and b) one or more isolated encoding nucleic acid molecules provided herein, protein encoded by such nucleic acid molecules, or fragments thereof.

According to some embodiments of the invention, methods of inducing or eliciting an immune response in mammals against a plurality of influenza viruses comprise administering to the mammals: a) the influenza strain H1N1 and influenza strain H5N1 consensus NA protein, functional fragments thereof, or expressible coding sequences thereof; and b) one or more isolated encoding nucleic acid molecules provided herein, protein encoded by such nucleic acid molecules, or fragments thereof.

According to some embodiments of the invention, methods of inducing or eliciting an immune response in mammals against a plurality of influenza viruses comprise administering to the mammals: a) the influenza strain H1N1 and influenza strain H5N1 consensus M1 protein, functional fragments thereof, or expressible coding sequences thereof; and b) one or more isolated encoding nucleic acid molecules provided herein, protein encoded by such nucleic acid molecules, or fragments thereof.

According to some embodiments of the invention, methods of inducing or eliciting an immune response in mammals against a plurality of influenza viruses comprise administering to the mammals: a) the influenza strain H5N1 M2E-NP consensus protein, functional fragments thereof, or expressible coding sequences thereof; and b) one or more isolated encoding nucleic acid molecules provided herein, protein encoded by such nucleic acid molecules, or fragments thereof.

According to some embodiments of the invention, methods of inducing or eliciting an immune response in mammals against a plurality of influenza viruses comprise administering to the mammals: a) the influenza strain H1N1 HA consensus protein, functional fragments thereof, or expressible coding sequences thereof; and b) one or more isolated encoding nucleic acid molecules provided herein, protein encoded by such nucleic acid molecules, or fragments thereof.

According to some embodiments of the invention, methods of inducing or eliciting an immune response in mammals against a plurality of influenza viruses comprise administering to the mammals: a) the influenza strain H3N1 HA consensus protein, functional fragments thereof, or expressible coding sequences thereof; and b) one or more isolated encoding nucleic acid molecules provided herein, protein encoded by such nucleic acid molecules, or fragments thereof.

In some embodiments of the invention, the vaccines of the invention include at least two of the following sequences: SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10, SEQ ID NO:11, SEQ ID NO:12, SEQ ID NO:13, and SEQ ID NO:14, or any combination of two or more sequences from the aforementioned list.

Vaccines

In some embodiments, the invention provides improved vaccines by providing proteins and genetic constructs that encode proteins with epitopes that make them particularly effective as immunogens against which immune responses can be induced. Accordingly, vaccines can be provided to induce a therapeutic or prophylactic immune response.

According to some embodiments of the invention, a vaccine according to the invention is delivered to an individual to modulate the activity of the individual's immune system and thereby enhance the immune response. When a nucleic acid molecule that encodes the protein is taken up by cells of the individual the nucleotide sequence is expressed in the cells and the protein are thereby delivered to the individual. Aspects of the invention provide methods of delivering the coding sequences of the protein on nucleic acid molecule such as plasmid.

According to some aspects of the present invention, compositions and methods are provided which prophylactically and/or therapeutically immunize an individual.

When taken up by a cell, the DNA plasmids can stay present in the cell as separate genetic material. Alternatively, RNA may be administered to the cell. It is also contemplated to provide the genetic construct as a linear minichromosome including a centromere, telomeres and an origin of replication. Genetic constructs include regulatory elements necessary for gene expression of a nucleic acid molecule. The elements include: a promoter, an initiation codon, a stop codon, and a polyadenylation signal. In addition, enhancers are often required for gene expression of the sequence that encodes the target protein or the immunomodulating protein. It is necessary that these elements be operable linked to the sequence that encodes the desired proteins and that the regulatory elements are operably in the individual to whom they are administered.

Initiation codons and stop codon are generally considered to be part of a nucleotide sequence that encodes the desired protein. However, it is necessary that these elements are functional in the mammals to whom the nucleic acid construct is administered. The initiation and termination codons must be in frame with the coding sequence.

Promoters and polyadenylation signals used must be functional within the cells of the individual.

Examples of promoters useful to practice the present invention, especially in the production of a genetic vaccine for humans, include but are not limited to promoters from simian virus 40 (SV40), mouse mammary tumor virus (MMTV) promoter, human immunodeficiency virus (HIV) such as the bovine immunodeficiency virus (BIV) long terminal repeat (LTR) promoter, Moloney virus, avian leukosis virus (ALV), cytomegalovirus (CMV) such as the CMV immediate early promoter, Epstein Barr virus (EBV), Rous sarcoma virus (RSV) as well as promoters from human genes such as human actin, human myosin, human hemoglobin, human muscle creatine and human metalothionein; in other embodiments, promoters can be tissue specific promoters, such as muscle or skin specific promoters, natural or synthetic. Examples of such promoters are described in US patent application publication no. US20040175727, which is incorporated hereby in its entirety.

Examples of polyadenylation signals useful to practice the present invention, especially in the production of a genetic vaccine for humans, include but are not limited to SV40 polyadenylation signals, LTR polyadenylation signals, bovine growth hormone (bGH) polyadenylation signals, human growth hormone (hGH) polyadenylation signals, and human β-globin polyadenylation signals. In particular, the SV40 polyadenylation signal that is in pCEP4 plasmid (Invitrogen, San Diego, Calif.), referred to as the SV40 polyadenylation signal, can be used.

In addition to the regulatory elements required for DNA expression, other elements may also be included in the DNA molecule. Such additional elements include enhancers. The enhancer may be selected from the group including but not limited to: human actin, human myosin, human hemoglobin, human muscle creatine and viral enhancers such as those from CMV, RSV and EBV.

Genetic constructs can be provided with mammalian origin of replication in order to maintain the construct extrachromosomally and produce multiple copies of the construct in the cell. Plasmids pVAX1, pCEP4 and pREP4 from Invitrogen (San Diego, Calif.) contain the Epstein Barr virus origin of replication and nuclear antigen EBNA-1 coding region which produces high copy episomal replication without integration.

In order to maximize protein production, regulatory sequences may be selected which are well suited for gene expression in the cells the construct is administered into. Moreover, codons that encode said protein may be selected which are most efficiently transcribed in the host cell. One having ordinary skill in the art can produce DNA constructs that are functional in the cells.

In some embodiments, nucleic acid constructs may be provided in which the coding sequences for the proteins described herein are linked to IgE signal peptide. In some embodiments, proteins described herein are linked to IgE signal peptide.

In some embodiments for which protein is used, for example, one having ordinary skill in the art can, using well known techniques, can produce and isolate proteins of the invention using well known techniques. In some embodiments for which protein is used, for example, one having ordinary skill in the art can, using well known techniques, inserts DNA molecules that encode a protein of the invention into a commercially available expression vector for use in well known expression systems. For example, the commercially available plasmid pSE420 (Invitrogen, San Diego, Calif.) may be used for production of protein in Escherichia coli (E. coli). The commercially available plasmid pYES2 (Invitrogen, San Diego, Calif.) may, for example, be used for production in Saccharomyces cerevisiae strains of yeast. The commercially available MAXBAC™ complete baculovirus expression system (Invitrogen, San Diego, Calif.) may, for example, be used for production in insect cells. The commercially available plasmid pcDNA I or pcDNA3 (Invitrogen, San Diego, Calif.) may, for example, be used for production in mammalian cells such as Chinese hamster ovary (CHO) cells. One having ordinary skill in the art can use these commercial expression vectors and systems or others to produce protein by routine techniques and readily available starting materials. (See e.g., Sambrook et al., Molecular Cloning a Laboratory Manual, Second Ed. Cold Spring Harbor Press (1989)). Thus, the desired proteins can be prepared in both prokaryotic and eukaryotic systems, resulting in a spectrum of processed forms of the protein.

One having ordinary skill in the art may use other commercially available expression vectors and systems or produce vectors using well known methods and readily available starting materials. Expression systems containing the requisite control sequences, such as promoters and polyadenylation signals, and preferably enhancers are readily available and known in the art for a variety of hosts. See e.g., Sambrook et al., Molecular Cloning a Laboratory Manual, Second Ed. Cold Spring Harbor Press (1989). Genetic constructs include the protein coding sequence operably linked to a promoter that is functional in the cell line, or cells of targeted tissue, into which the constructs are transfected. Examples of constitutive promoters include promoters from cytomegalovirus (CMV) or SV40. Examples of inducible promoters include mouse mammary leukemia virus or metallothionein promoters. Those having ordinary skill in the art can readily produce genetic constructs useful for transfecting cells with DNA that encodes protein of the invention from readily available starting materials. The expression vector including the DNA that encodes the protein is used to transform the compatible host which is then cultured and maintained under conditions wherein expression of the foreign DNA takes place.

The protein produced is recovered from the culture, either by lysing the cells or from the culture medium as appropriate and known to those in the art. One having ordinary skill in the art can, using well known techniques, isolate protein that is produced using such expression systems. The methods of purifying protein from natural sources using antibodies which specifically bind to a specific protein as described above may be equally applied to purifying protein produced by recombinant DNA methodology.

In addition to producing proteins by recombinant techniques, automated peptide synthesizers may also be employed to produce isolated, essentially pure protein. Such techniques are well known to those having ordinary skill in the art and are useful if derivatives which have substitutions not provided for in DNA-encoded protein production.

The nucleic acid molecules may be delivered using any of several well known technologies including DNA injection (also referred to as DNA vaccination) with and without in vivo electroporation, liposome mediated, nanoparticle facilitated, recombinant vectors such as recombinant adenovirus, recombinant adenovirus associated virus and recombinant vaccinia. Preferably, the nucleic acid molecules such as the DNA plasmids described herein are delivered via DNA injection and along with in vivo electroporation.

Routes of administration include, but are not limited to, intramuscular, intransally, intraperitoneal, intradermal, subcutaneous, intravenous, intraarterially, intraoccularly and oral as well as topically, transdermally, by inhalation or suppository or to mucosal tissue such as by lavage to vaginal, rectal, urethral, buccal and sublingual tissue. Preferred routes of administration include intramuscular, intraperitoneal, intradermal and subcutaneous injection. Genetic constructs may be administered by means including, but not limited to, traditional syringes, needleless injection devices, “microprojectile bombardment gone guns”, or other physical methods such as electroporation (“EP”), “hydrodynamic method”, or ultrasound.

Examples of electroporation devices and electroporation methods preferred for facilitating delivery of the DNA vaccines of the present invention, include those described in U.S. Pat. No. 7,245,963 by Draghia-Akli, et al., U.S. Patent Pub. 2005/0052630 submitted by Smith, et al., the contents of which are hereby incorporated by reference in their entirety. Also preferred, are electroporation devices and electroporation methods for facilitating delivery of the DNA vaccines provided in co-pending and co-owned U.S. patent application Ser. No. 11/874,072, filed Oct. 17, 2007, which claims the benefit under 35 USC 119(e) to U.S. Provisional Applications Ser. Nos. 60/852,149, filed Oct. 17, 2006, and 60/978,982, filed Oct. 10, 2007, all of which are hereby incorporated in their entirety. Preferable, the electroporation device is the CELLECTRA™ device (VGX Pharmaceuticals, Blue Bell, Pa.), including the intramuscular (IM) and intradermal (ID) models.

U.S. Pat. No. 7,245,963 by Draghia-Akli, et al. describes modular electrode systems and their use for facilitating the introduction of a biomolecule into cells of a selected tissue in a body or plant. The modular electrode systems comprise a plurality of needle electrodes; a hypodermic needle; an electrical connector that provides a conductive link from a programmable constant-current pulse controller to the plurality of needle electrodes; and a power source. An operator can grasp the plurality of needle electrodes that are mounted on a support structure and firmly insert them into the selected tissue in a body or plant. The biomolecules are then delivered via the hypodermic needle into the selected tissue. The programmable constant-current pulse controller is activated and constant-current electrical pulse is applied to the plurality of needle electrodes. The applied constant-current electrical pulse facilitates the introduction of the biomolecule into the cell between the plurality of electrodes. The entire content of U.S. Pat. No. 7,245,963 is hereby incorporated by reference.

U.S. Patent Pub. 2005/0052630 submitted by Smith, et al. describes an electroporation device which may be used to effectively facilitate the introduction of a biomolecule into cells of a selected tissue in a body or plant. The electroporation device comprises an electro-kinetic device (“EKD device”) whose operation is specified by software or firmware. The EKD device produces a series of programmable constant-current pulse patterns between electrodes in an array based on user control and input of the pulse parameters, and allows the storage and acquisition of current waveform data. The electroporation device also comprises a replaceable electrode disk having an array of needle electrodes, a central injection channel for an injection needle, and a removable guide disk. The entire content of U.S. Patent Pub. 2005/0052630 is hereby incorporated by reference.

The electrode arrays and methods described in U.S. Pat. No. 7,245,963 and U.S. Patent Pub. 2005/0052630 are adapted for deep penetration into not only tissues such as muscle, but also other tissues or organs. Because of the configuration of the electrode array, the injection needle (to deliver the biomolecule of choice) is also inserted completely into the target organ, and the injection is administered perpendicular to the target issue, in the area that is pre-delineated by the electrodes The electrodes described in U.S. Pat. No. 7,245,963 and U.S. Patent Pub. 2005/005263 are preferably 20 mm long and 21 gauge.

The following is an example of methods of the present invention, and is discussed in more detail in the patent references discussed above: electroporation devices can be configured to deliver to a desired tissue of a mammal a pulse of energy producing a constant current similar to a preset current input by a user. The electroporation device comprises an electroporation component and an electrode assembly or handle assembly. The electroporation component can include and incorporate one or more of the various elements of the electroporation devices, including: controller, current waveform generator, impedance tester, waveform logger, input element, status reporting element, communication port, memory component, power source, and power switch. The electroporation component can function as one element of the electroporation devices, and the other elements are separate elements (or components) in communication with the electroporation component. In some embodiments, the electroporation component can function as more than one element of the electroporation devices, which can be in communication with still other elements of the electroporation devices separate from the electroporation component. The present invention is not limited by the elements of the electroporation devices existing as parts of one electromechanical or mechanical device, as the elements can function as one device or as separate elements in communication with one another. The electroporation component is capable of delivering the pulse of energy that produces the constant current in the desired tissue, and includes a feedback mechanism. The electrode assembly includes an electrode array having a plurality of electrodes in a spatial arrangement, wherein the electrode assembly receives the pulse of energy from the electroporation component and delivers same to the desired tissue through the electrodes. At least one of the plurality of electrodes is neutral during delivery of the pulse of energy and measures impedance in the desired tissue and communicates the impedance to the electroporation component. The feedback mechanism can receive the measured impedance and can adjust the pulse of energy delivered by the electroporation component to maintain the constant current.

In some embodiments, the plurality of electrodes can deliver the pulse of energy in a decentralized pattern. In some embodiments, the plurality of electrodes can deliver the pulse of energy in the decentralized pattern through the control of the electrodes under a programmed sequence, and the programmed sequence is input by a user to the electroporation component. In some embodiments, the programmed sequence comprises a plurality of pulses delivered in sequence, wherein each pulse of the plurality of pulses is delivered by at least two active electrodes with one neutral electrode that measures impedance, and wherein a subsequent pulse of the plurality of pulses is delivered by a different one of at least two active electrodes with one neutral electrode that measures impedance.

In some embodiments, the feedback mechanism is performed by either hardware or software. Preferably, the feedback mechanism is performed by an analog closed-loop circuit. Preferably, this feedback occurs every 50 μs, 20 μs, 10 μs or 1 μs, but is preferably a real-time feedback or instantaneous (i.e., substantially instantaneous as determined by available techniques for determining response time). In some embodiments, the neutral electrode measures the impedance in the desired tissue and communicates the impedance to the feedback mechanism, and the feedback mechanism responds to the impedance and adjusts the pulse of energy to maintain the constant current at a value similar to the preset current. In some embodiments, the feedback mechanism maintains the constant current continuously and instantaneously during the delivery of the pulse of energy.

A pharmaceutically acceptable excipient can include such functional molecules as vehicles, adjuvants, carriers or diluents, which are known and readily available to the public. Preferably, the pharmaceutically acceptable excipient is an adjuvant or transfection facilitating agent. In some embodiments, the nucleic acid molecule, or DNA plasmid, is delivered to the cells in conjunction with administration of a polynucleotide function enhancer or a genetic vaccine facilitator agent (or transfection facilitating agent). Polynucleotide function enhancers are described in U.S. Pat. Nos. 5,593,972, 5,962,428 and International Application Serial Number PCT/US94/00899 filed Jan. 26, 1994, which are each incorporated herein by reference. Genetic vaccine facilitator agents are described in U.S. Ser. No. 021,579 filed Apr. 1, 1994, which is incorporated herein by reference. The transfection facilitating agent can be administered in conjunction with nucleic acid molecules as a mixture with the nucleic acid molecule or administered separately simultaneously, before or after administration of nucleic acid molecules. Examples of transfection facilitating agents includes surface active agents such as immune-stimulating complexes (ISCOMS), Freunds incomplete adjuvant, LPS analog including monophosphoryl lipid A, muramyl peptides, quinone analogs and vesicles such as squalene and squalene, and hyaluronic acid may also be used administered in conjunction with the genetic construct. In some embodiments, the DNA plasmid vaccines may also include a transfection facilitating agent such as lipids, liposomes, including lecithin liposomes or other liposomes known in the art, as a DNA-liposome mixture (see for example W09324640), calcium ions, viral proteins, polyanions, polycations, or nanoparticles, or other known transfection facilitating agents. Preferably, the transfection facilitating agent is a polyanion, polycation, including poly-L-glutamate (LGS), or lipid.

In some preferred embodiments, the DNA plasmids are delivered with an adjuvant that are genes for proteins which further enhance the immune response against such target proteins. Examples of such genes are those which encode other cytokines and lymphokines such as alpha-interferon, gamma-interferon, platelet derived growth factor (PDGF), TNFα, TNFβ, GM-CSF, epidermal growth factor (EGF), IL-1, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, IL-18, MHC, CD80, CD86 and IL-15 including IL-15 having the signal sequence deleted and optionally including the signal peptide from IgE. Other genes which may be useful include those encoding: MCP-1, MIP-1α, MIP-1p, IL-8, RANTES, L-selectin, P-selectin, E-selectin, CD34, GlyCAM-1, MadCAM-1, LFA-1, VLA-1, Mac-1, pl50.95, PECAM, ICAM-1, ICAM-2, ICAM-3, CD2, LFA-3, M-CSF, G-CSF, IL-4, mutant forms of IL-18, CD40, CD40L, vascular growth factor, fibroblast growth factor, IL-7, nerve growth factor, vascular endothelial growth factor, Fas, TNF receptor, Flt, Apo-1, p55, WSL-1, DR3, TRAMP, Apo-3, AIR, LARD, NGRF, DR4, DR5, KILLER, TRAIL-R2, TRICK2, DR6, Caspase ICE, Fos, c-jun, Sp-1, Ap-1, Ap-2, p38, p65Rel, MyD88, IRAK, TRAF6, IkB, Inactive NIK, SAP K, SAP-1, JNK, interferon response genes, NFkB, Bax, TRAIL, TRAILrec, TRAILrecDRC5, TRAIL-R3, TRAIL-R4, RANK, RANK LIGAND, Ox40, Ox40 LIGAND, NKG2D, MICA, MICB, NKG2A, NKG2B, NKG2C, NKG2E, NKG2F, TAP1, TAP2 and functional fragments thereof.

The pharmaceutical compositions according to the present invention comprise DNA quantities of from about 1 nanogram to 100 milligrams; about 1 microgram to about 10 milligrams; or preferably about 0.1 microgram to about 10 milligrams; or more preferably about 1 milligram to about 2 milligram. In some preferred embodiments, pharmaceutical compositions according to the present invention comprise about 5 nanogram to about 1000 micrograms of DNA. In some preferred embodiments, the pharmaceutical compositions contain about 10 nanograms to about 800 micrograms of DNA. In some preferred embodiments, the pharmaceutical compositions contain about 0.1 to about 500 micrograms of DNA. In some preferred embodiments, the pharmaceutical compositions contain about 1 to about 350 micrograms of DNA. In some preferred embodiments, the pharmaceutical compositions contain about 25 to about 250 micrograms of DNA. In some preferred embodiments, the pharmaceutical compositions contain about 100 to about 200 microgram DNA.

The pharmaceutical compositions according to the present invention are formulated according to the mode of administration to be used. In cases where pharmaceutical compositions are injectable pharmaceutical compositions, they are sterile, pyrogen free and particulate free. An isotonic formulation is preferably used. Generally, additives for isotonicity can include sodium chloride, dextrose, mannitol, sorbitol and lactose. In some cases, isotonic solutions such as phosphate buffered saline are preferred. Stabilizers include gelatin and albumin. In some embodiments, a vasoconstriction agent is added to the formulation. In some embodiments, a stabilizing agent that allows the formulation to be stable at room or ambient temperature for extended periods of time, such as LGS or other polycations or polyanions is added to the formulation.

In some embodiments, methods of eliciting an immune response in mammals against a consensus influenza antigen include methods of inducing mucosal immune responses. Such methods include administering to the mammal one or more of CTACK protein, TECK protein, MEC protein and functional fragments thereof or expressible coding sequences thereof in combination with an DNA plasmid including a consensus influenza antigen, described above. The one or more of CTACK protein, TECK protein, MEC protein and functional fragments thereof may be administered prior to, simultaneously with or after administration of the DNA plasmid influenza vaccines provided herein. In some embodiments, an isolated nucleic acid molecule that encodes one or more proteins of selected from the group consisting of: CTACK, TECK, MEC and functional fragments thereof is administered to the mammal.

EXAMPLES

The present invention is further illustrated in the following Examples. It should be understood that these Examples, while indicating preferred embodiments of the invention, are given by way of illustration only. From the above discussion and these Examples, one skilled in the art can ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. Thus, various modifications of the invention in addition to those shown and described herein will be apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims.

Preferably the DNA formulations for use with a muscle or skin EP device described herein have high DNA concentrations, preferably concentrations that include milligram to tens of milligram quantities, and preferably tens of milligram quantities, of DNA in small volumes that are optimal for delivery to the skin, preferably small injection volume, ideally 25-200 microliters (μL). In some embodiments, the DNA formulations have high DNA concentrations, such as 1 mg/mL or greater (mg DNA/volume of formulation). More preferably, the DNA formulation has a DNA concentration that provides for gram quantities of DNA in 200 μL of formula, and more preferably gram quantities of DNA in 100 μL of formula.

The DNA plasmids for use with the EP devices of the present invention can be formulated or manufactured using a combination of known devices and techniques, but preferably they are manufactured using an optimized plasmid manufacturing technique that is described in a commonly owned, co-pending U.S. provisional application U.S. Ser. No. 60/939,792, which was filed on May 23, 2007. In some examples, the DNA plasmids used in these studies can be formulated at concentrations greater than or equal to 10 mg/mL. The manufacturing techniques also include or incorporate various devices and protocols that are commonly known to those of ordinary skill in the art, in addition to those described in U.S. Ser. No. 60/939,792, including those described in a commonly owned patent, U.S. Pat. No. 7,238,522, which issued on Jul. 3, 2007. The high concentrations of plasmids used with the skin EP devices and delivery techniques described herein allow for administration of plasmids into the ID/SC space in a reasonably low volume and aids in enhancing expression and immunization effects. The commonly owned application and patent, U.S. Ser. No. 60/939,792 and U.S. Pat. No. 7,238,522, respectively, are hereby incorporated in their entirety.

Example 1 Plasmid Constructs

A ubiquitous cytomegalovirus (CMV) promoter drives the expression of human secreted embryonic alkaline phosphatase (SEAP) reporter transgene product in the pCMV-SEAP vector. Plasmids were obtained using a commercially available kit (Qiagen Inc., Chatsworth, Calif.). Endotoxin levels were at less than 0.01 EU/μg, as measured by Kinetic Chromagenic LAL (Endosafe, Charleston, S.C.). Consensus HA and NA constructs were generated by analyzing primary virus sequences from 16H5 viruses that have proven fatal to humans in recent years, and over 40 human N1 viruses. These sequences were downloaded from the Los Alamos National Laboratory's Influenza Sequence Database. After generating the consensus sequences, the constructs were optimized for mammalian expression, including the addition of a Kozak sequence, codon optimization, and RNA optimization. These constructs were then subcloned into the pVAX vector (Invitrogen, Carlsbad, Calif.). Unless indicated otherwise, plasmid preparations were diluted in sterile water and formulated 1% weight/weight with poly-L-glutamate sodium salt (LGS) (MW=10.5 kDa average)(Sigma, St. Louis, Mo.), further HPLC purified at VGX Pharmaceuticals, Immune Therapeutics Division (The Woodlands, Tex.).

Example 2 Treatment of Pigs

Pigs were divided into 10 groups×4 pigs per group for a total of 40 pigs (Table 1). Pigs were acclimated for 4 days, weighed and ear-tagged. On Study Day 0, pigs were weighed, bled and anesthetized using a combination pre-anesthetic for pigs—ketamine—(20 mg/kg), xylazine—(2.2 mg/kg) and atropine (0.04 mg/kg), and then anesthetized using isoflurane (induction at 5%, maintenance at 2-3%). Pigs (n=4/group) were injected with 0.6 mL of CMV-HA (a pVAX based construct that expresses a consensus H5 antigen), CMV-NA (a pVAX based construct that expresses a consensus N1 antigen), and CMV-SEAP (a construct expressing the reporter gene secreated ambryonic alkaline phosphatase, SEAP) plasmid (the last one added to increase plasmid concentration, and viscosity of the solution for the “muscle damage” assessment)+1.0% wt/wt LGS at varying plasmid concentrations and current intensities. The plasmids were prepared according to the materials and methods provided in Example 1. After 4s, animals were electroporated using the adaptive constant current CELLECTRA™ intramuscular (IM) system (VGX Pharmaceuticals, Blue Bell, Pa.) equipped with 5 needle electrodes and operated with the following pulse parameters: 52 millisecond pulses, 1 second between pulses, 3 pulses with varying current (0.1, 0.3 and 0.5 A).

TABLE 1 Groups for the pig vaccine experiment Con- Conc struct Total Injec- (mg/ (mg)/ Dose tion Group Plasmid mL) pig (mg/pig) Volume A n 1 HA, NA, 10 2 6 600 μl 0.5 4 SEAP 2 HA, NA, 4 0.8 2.4 600 μl 0.5 4 SEAP 3 HA, NA, 1.5 0.1 0.3 600 μl 0.5 4 SEAP 4 HA, NA, 10 2 6 600 μl 0.3 4 SEAP 5 HA, NA, 4 0.8 2.4 600 μl 0.3 4 SEAP 6 HA, NA, 1.5 0.1 0.3 600 μl 0.3 4 SEAP 7 HA, NA, 10 2 6 600 μl 0.1 4 SEAP 8 HA, NA, 4 0.8 2.4 600 μl 0.1 4 SEAP 9 HA, NA, 1.5 0.1 0.3 600 μl 0.1 4 SEAP 10 None N/A N/A N/A N/A N/A 4 The area surrounding each injection site was tattooed for rapid identification for biopsy at Days 14 and 35 post-injection.

Pigs were allowed to recover from anesthesia and were closely monitored for 24 hours to ensure full recovery. Any pigs that did not fully recover within 2 to 3 hours post-treatment were noted. Pigs were weighed and bled on Day 10, Day 21 and Day 35. The pigs were administered a second vaccination on Day 21. Blood was collected in 2 purple top tubes, 1.0 mL for CBC and differentials (Antech Diagnostics, Irvine, Calif.); 10 mL for IFN-γ ELISpots against HA and NA antigens, and separate falcon tubes which were allowed to clot and centrifuged to isolate serum then aliquoted into tubes on ice. On Day 35, all pigs were exsanguinated under surgical plane of anesthesia and needle punch biopsies of the injection sites were taken for histology.

Hemagglutination Inhibition (HI) Assay

Pig sera were treated with receptor destroying enzyme (RDE) by diluting one part serum with three parts enzyme and incubated overnight in 37° C. water bath. The enzyme was inactivated by 30 min incubation at 56° C. followed by addition of six parts PBS for a final dilution of 1/10. HI assays were performed in V-bottom 96-well microtiter plates, using four HA units of virus and 1% horse red blood cells as previously described (Stephenson, I., et al., Virus Res., 103(1-2):91-5 (July 2004)).

The highest titers as demonstrated by the HI assay (FIG. 2) were found in sera from the group administered 2 mg of HA-expressing plasmid at a current setting of 0.5 A (120±40; P=0.11 versus 2 mg/0.3 A and P=0.02 versus 2 mg/0.1 A); the titers decreased with the intensity of the electric field for the group that received 2 mg of each plasmid; if either plasmid quantity of current were decreased thereafter, the titers were more variable, and non-different between groups.

The HI titers were highest in the group administered 2 mg of HA-expressing plasmid and electroporated at 0.5 A. Furthermore, the titers decline with descending plasmid doses in the group electroporated at 0.5 A, and with the intensity of the electric field. The lower plasmid quantities or lower current intensities appeared to increase the intra-group variability.

HA and NA IFN-γ ELISpots

ELISpot were performed as previously described using IFN-γ capture and detection antibodies (MabTech, Sweden) (Boyer J D, et al., J Med Primatol, 34(5-6):262-70 (October 2005)). Antigen-specific responses were determined by subtracting the number of spots in the negative control wells from the wells containing peptides. Results are shown as the mean value (spots/million splenocytes) obtained for triplicate wells.

The group administered 2 mg of each plasmid (for a total of 4 mg) at a current setting of 0.3 A attained the highest cellular immune response as measured by the IFN-γ ELISpot of 537±322 SFU per million cells. The average responses of all other groups were within background levels of the assay. The individual ELISpot responses of two animals attaining the highest cellular immune response are highlighted in FIG. 3.

CBC Results

Lymphocytes reached the highest levels at Day 21 of the study and in the groups administered the highest dose of vaccines, regardless of current setting, although the groups with the highest dose (4 mg of total plasmid, 2 mg each) and highest current setting (0.5 A) demonstrates highest lymphocyte response, 40% higher than controls (12670±1412 vs. 7607±1603 lymphocyte counts/100 blood, respectively; P<0.002).

Muscle Histopathology

The injection sites were identified and punch biopsies were taken at Days 14 and 35 post-treatment after the pigs were exsanguinated. The tissues were fixed in buffered formalin for 24 hours then washed 3× in PBS and stored in 70% alcohol. The biopsy samples were submitted to Antech Diagnostics where they were processed and sections stained with hematoxylin and eosin (H&E). All the slides were evaluated by a single board-certified pathologist who scored them 0 to 5 for pathological criteria (Table 2) in various tissue layers (Table 3). The mean score was calculated for each group at each time point.

TABLE 2 Biopsy pathology scoring parameters Score Criteria 0 Not present, no inflammatory cells 1 Minimal, 1-20 inflammatory cells/100 × high-powered field (HPF) 2 Mild, 21-40 inflammatory cells/100 × HPF 3 Moderate, 41-75 inflammatory cells/100 × HPF 4 Moderate to Marked/Severe, 76-100 inflammatory cells/100 × HPF 5 Marked Severe, >100 inflammatory cells/100 × HPF

TABLE 3 Biopsy tissue layers and pathological parameters Anatomy Location Pathology Parameter Dermal Superficial neovascularization Dermal Pylogranulomatous inflammation Dermal Overlying erosion & inflammatory crusting Dermal Focal fibrosis Subcutaneous Pylogranulomatous inflammation with intralesional collagen necrosis Subcutaneous Lymphacytic and plasmalytic inflammation Skeletal muscle Lymphacytic and plasmalytic and eosinophilic inflammation Skeletal muscle Myocyte degeneration/necrosis Skeletal muscle Fibrosis

The histopathology was scored from the muscle biopsy (FIG. 4A) at 14 and 35 days after plasmid injection and EP based on a 0 to 5 scale criteria (Table 2). Overall pathology scores following electroporation declined in the tissue layers (Table 3) from Day 14 to Day 35. The group that received 6 mg of total plasmid at 0.3 A settings exhibited the highest total pathology scores at Day 14 (18.3±6.4, P<0.0002 versus control), correlating with the highest average lymphocyte responses. All pathology scores at Day 35 approached levels of non-treated control levels (range of 6.67 to 4.25). Nevertheless, when the muscle necrosis and fibrosis (typically associated with the EP procedure) (Gronevik E, et al., J Gene Med, 7(2):218-27 (2005 February)). were analyzed separately (FIG. 4B), the scores ranged between 1 and 2, with no difference between groups or between treated groups and controls, while the higher scores were associated with lymphatic, plasmacytic or eosinophilic inflammation due to immune responses. Significantly, these scores also declined from day 14 to day 35 post-treatment.

Data Analysis

Data were analyzed using Microsoft Excel Statistics package. Values shown in the figures are the mean±SEM. Specific values were obtained by comparison using one-way ANOVA and subsequent t-test. A value of p<0.05 was set as the level of statistical significance.

Example 3 Treatment of Ferrets

Twenty male ferrets (Triple F Farms, Sayre, Pa.), 4-6 months of age or at least 1 kg body weight, were used in this study and housed at BIOQUAL, Inc. (Rockville, Md.). The ferret study design is in Table 4. Animals were allowed to acclimate for two weeks prior to the study. Animals were immunized (under anesthesia) at Week 0, 4, and 9. Blood was drawn every 2 weeks. After the third immunization, animals were moved into a BSL-3 facility and challenged at Week 13 with a very potent strain of avian influenza (H5N1) and then followed for two more weeks post-challenge. For two weeks after challenge, animals were monitored daily, and body weights, temperature and clinical scores were recorded. Activity level was monitored and recorded; death were documented.

This study tested the efficacy of HA, NA and M2e-NP DNA vaccine delivered IM followed by electroporation using the CELLECTRA™ adaptive constant current electroporation intramuscular (IM) system (VGX Pharmaceuticals, Blue Bell, Pa.) in an influenza challenge model in ferrets. The DNA plasmids were prepared according to the materials and methods provided in Example 1. As outlined in Table 4, animals in Groups 2, 3 and 4 received 0.2 mg of the respective influenza plasmid vaccine. In order to correct for dose, groups which received 1 plasmid vaccine (Groups 2 and 3) or no vaccine (control Group 1), the difference was made up by pVAX empty vector such that all animals in every group received a total dose of 0.6 mg of plasmid. The conditions of electroporation were, using a 5 needle electrode array: 0.5 Amps, 52 msec pulse width, 1 sec between pulses, 4 sec delay between injection and electroporation.

TABLE 4 Groups for the Influenza challenge experiment in ferrets Total Vaccine vaccine in Dose (mg) Total Group Plasmids/Antigens per Plasmid volume n 1 None (pVAX only)   0 mg 0.6 mg 4 in 0.6 mL 2 H5 + pVAX 0.2 mg 0.6 mg 4 in 0.6 mL 3 NA + pVAX 0.2 mg 0.6 mg 4 in 0.6 mL 4 H5, NA, M2e-NP 0.2 mg 0.6 mg 4 in 0.6 mL

Hemagglutination Inhibition (HI) Assay

Sera were treated with receptor destroying enzyme (RDE) by diluting one part serum with three parts enzyme and incubated overnight in 37° C. water bath. The enzyme was inactivated by 30 min incubation at 56° C. followed by addition of six parts PBS for a final dilution of 1/10. HI assays were performed in V-bottom 96-well microtiter plates, using four HA units of virus and 1% horse red blood cells as previously described (Stephenson, I., et al., Virus Res., 103(1-2):91-5 (July 2004)). The viruses used for the HI assay are reassortant strains we obtained from the Center for Disease Control: A/Viet/1203/2004(H5N1)/PR8-IBCDC-RG (clade 1 virus) and A/Indo/05/2005 (H5N1)/PR8-IBCDC-RG2 (clade 2 virus). The ferret model of influenza infection is considered to be more reflective of human disease and a more rigorous challenge model. Ferrets exhibit similar symptoms to humans infected with influenza and similar tissue tropism with regards to human and avian influenza viruses. Serum collected at different time points throughout the study was used to detect HI activity against H5N1 viruses. As shown in FIG. 7, both groups containing the consensus H5 specific HA construct attained protective levels of antibody (>1:40) after two immunizations and were also able to inhibit a clade 2 H5N1 virus. In other words, the HI assay was positive against both viral strains despite the consensus HA strain was based on clade 1 viruses.

Data Analysis

Data were analyzed using Microsoft Excel Statistics package. Values shown in the figures are the mean±SEM. Specific values were obtained by comparison using one-way ANOVA and subsequent t-test. A value of p<0.05 was set as the level of statistical significance.

Ferret Influenza Challenge

The results of the influenza challenge are depicted in FIGS. 5 and 6. Control animals lost 25% of their body weight on average post-challenge (FIG. 5), while animals vaccinated with HA (Group 1) or HA+M2e-NP+NA (Group 4) lost between 9 and 10% (*P<0.004 versus controls). Body temperatures were elevated in control animals until all control animals were either found dead or euthanized by Day 8 (FIG. 6). All animals vaccinated, regardless of which vaccine regimen, survived the challenge and showed fewer signs of infection as compared to the control animals as evidenced by their clinical scores (Table 5). Control animals worsen as far as clinical scores (nasal discharge, cough, lethargy), and died between day 5 and day 7 post-challenge. As shown in Table 5, the severity of the clinical scores in vaccinated animals was inversely correlated with the antibody titers (higher antibody titers, lower clinical scores, better clinical outcome).

TABLE 5 Results for Challenged Ferrets Post-challenge Observations HI Titers 3 wks Vaccines Ferret Day 1 Day 2 Day 3 Day 5 Day 6 Day 7 Day 8 Day 9 Pre-challenge 891 0_1 1_1 1_1 0_1 0_1  1_1* <20 Control 890 0_1 0_1 1_1  0_1* <20 (pVAX) 877 0_1 0_1 1_1 0_2 2_3 FD <20 876 0_1 0_1 0_1 0_1 2_3  1_3* <20 878 0_1 0_1 1_1 0_1 0_1 0_1 0_1 0_1 40 H5 879 0_1 0_1 0_1 0_1 0_1 0_1 0_1 0_1 320 888 0_1 0_1 0_1 0_1 0_1 0_1 0_1 0_1 160 889 0_1 0_1 0_1 0_1 0_1 0_1 0_1 0_1 320 881 0_1 0_1 1_0 0_1 0_1 1_1 0_1 0_1 <20 M2-NP 880 0_1 0_1 0_0 0_1 0_1 0_1 0_1 0_1 <20 883 0_1 1_1 1_1 0_1 0_1 1_1 0_1 0_1 <20 882 0_1 0_1 1_1 0_1 0_1 1_2 0_2 0_1 <20 885 0_1 0_1 0_1 0_1 0_1 0_1 0_1 0_1 1280 H5 + M2 − 884 0_1 0_1 0_1 0_1 0_1 0_1 0_1 0_1 320 NP + NA 886 1_1 1_1 0_1 0_1 0_1 1_1 0_1 1_1 160 887 0_1 1_1 0_0 0_1 0_1 1_1 0_1 0_1 640 Table 5 Note: Clinical scores are depicted for the post-challenge observation period. A “*” indicates the animal was euthanized; FD = found dead. The first clinical score in each column is for nasal symptoms: 0 = none; 1 = nasal discharge; 2 = breathing from mouth. The second score is for activity: 0 = sleeping; 1 = bright and alert; 2 = alert but nonresponsive; 3 = lethargic. The HI titers for each animal measured 3 weeks pre-challenge are depicted for comparison purposes.

Example 4 Intradermal Delivery Comparisons with Intramuscular Delivery in Primates

Rhesus macaques were immunized in these studies. Animals were acclimated for 2 months prior to the start of experiments. The study progressed as follows: Week 0—performed 1st immunization (plasmid dose administration) and baseline bleed; Week 2 performed bleed; Week 3 performed 2nd immunization (plasmid dose administration); Week 5 performed bleed; Week 6 performed 3rd immunization (plasmid dose administration) and bleed; Week 8 performed bleed.

TABLE 6 Total Study DNA DNA Group Constructs Nr. Route of Admin Dose (mg) A DNA 6 + 9 5 IM CELLECTRA ™ EP 1 mg/ 2 Const B DNA 6 + 9 5 ID CELLECTRA ™ EP 1 mg/ 2 Const C DNA 1 + 6 + 5 IM Syringe 1 mg/ 4 9 + 10 Const D Negative 5 N/A 0 Control DNA Construct # Encoding Antigen 1 Non-influenza antigen control plasmid 6 Influenza H5 consensus 9 Non-influenza antigen control plasmid 10 Non-influenza antigen control plasmid

All plasmids were formulated at 10 mg/mL in water for injection+1% LGS, as described in previous examples, above, and mixed into a single solution PER STUDY GROUP(S) (Groups C, D, G, and H, in above table, Table 6). The correct injection volume for each group designated IM CELLECTRA™ EP (VGX Pharmaceuticals), ID CELLECTRA™ EP (VGX Pharmaceuticals), and IM Syringe was calculated. For the ID administration, if the required injection volume surpassed 100 μL per site, the formulation was split into a number of injection sites (2, 3, or 6 depending on how many total mg of vaccine were administered). The animals that received IM injection(s) were given the entire formulation in one single site.

The CELLECTRA™ adaptive constant current device used in the pigs experiments, ferret experiments and nonhuman experiments described in the Examples. The electroporation conditions were as following: for the IM injection and electroporation groups the conditions were: 0.5 Amps, 52 msec/pulse, three pulses, 4 sec delay between plasmid injection and electroporation. For the ID injection and electroporation groups the conditions were: 0.2 Amps, 52 msec/pulse, three pulses, 4 sec delay between plasmid injection and electroporation.

Hemagglutination Inhibition (HI) Assay—monkey sera were treated with receptor destroying enzyme (RDE) by diluting one part serum with three parts enzyme and incubated overnight in 37° C. water bath. The enzyme was inactivated by 30 min incubation at 56° C. followed by addition of six parts PBS for a final dilution of 1/10. HI assays were performed in V-bottom 96-well microtiter plates, using four HA units of virus and 1% horse red blood cells. The data presented herein are the results after the second immunization (bleed collected before the third immunization).

HI titers were measured three weeks after the second immunization. The results can be seen displayed in the graph in FIG. 8. Monkeys receiving the HA plasmid vaccine via ID injection followed by electroporation demonstrated more than twice the average titers of the IM+EP group and almost three times the average titers of the IM group alone (*P<0.03). Non-treated controls did not exhibit any HI titers.

Example 5 Cross Protection in Primates Using Delivery Method—ID Injection Followed by Electroporation (EP)

Studies in non-human primates with the influenza vaccine (including H5, NA and M2e-NP consensus antigens, see above) indicated that ID injection followed by electroporation elicited higher antibody responses to the vaccine antigens than in IM injections. In one of our non-human primate studies (NHP) animals were vaccinated per Table 7.

TABLE 7 Study design and conditions. Rhesus macaques were immunized at weeks 0, 4, and 8. Concentration Group n/group Antigen Delivery (mg/plasmid) EP Conditions 1 5 pVax (sham) IM 1 mg/construct 0.5 Amps, 3 pulses, 52 msec, 1 sec between pulses 2 5 H5, NA, IM 1 mg/construct 0.5 Amps, 3 pulses, 52 msec, 1 sec M2e-NP between pulses 3 5 M2e-NP IM 1 mg/construct 0.5 Amps, 3 pulses, 52 msec, 1 sec between pulses 4 5 H5, NA, ID 1 mg/construct 0.2 Amps, 2 × 2 pulses, 52 msec, 1 sec M2e-NP between pulses Each animal received three vaccinations, and HAI titers and microneutralization were performed for both the same clade and cross-clades. As shown, the consensus vaccine offered broad protection not only within the same clade, but also cross-clades. Results are included in Table 8.

TABLE 8 Results of hemagglutination (HAI) and microneutralization assays. Clade 1 Clade 2.1 Clade 2.2 Clade 2.3.4 A/Vietnam A/Indonesia A/Turkey A/Anhui HAI Assay 2nd immunization VGX-3400IM 160 (80-320)  36 (20-80) 110 (0-320)^(4/5) 80 (40-160) VGX-3400ID 664 (40-1280) 120 (20-320) 205 (0-320)^(4/5) 592 (40-1280) 3rd immunization VGX-3400IM 288 (160-640) 32 (0-80)^(3/5) 36 (20-80) 84 (20-160) VGX-3400ID 416 (160-640) 64 (0-160)^(2/5) 145 (20-320) 276 (20-640) Microneutralization 3rd immunization VGX-3400IM 144 (40-360)  8 (0-40)^(1/5) 32 (0-80)^(2/5) 88 (0-160)^(4/5) VGX-3400ID 740 (20-2560) 96 (0-320)^(3/5) 296 (0-1280)^(3/5) 1172 (20-2560) Values presented indicate the mean titer, the range (in parenthesis) and the number of responders if less than 5/5 (in superscript). Note: HAI titers > 1:20 are generally considered seroprotective in the NHP model.

The needles in the ID electroporation device are much shorter (˜5 mm), of a lower gauge, and do not elicit muscle contractions or visible pain responses in the animals tested to date. Furthermore, the required electric field for efficacious ID EP is lower than that required for an optimum IM delivery. ID injection has been shown to elicit better immune responses to influenza vaccine antigens. (Holland D, et. al. (2008). J Inf Dis. 198:650-58.) Usually, a lower dose is needed in vaccines delivered ID compared to IM delivery to achieve similar humoral responses. 

1. A DNA plasmid vaccine capable of generating in a mammal an immune response against a plurality of influenza virus subtypes, comprising: a DNA plasmid capable of expressing a consensus influenza antigen in a cell of the mammal in a quantity effective to elicit an immune response in the mammal, the consensus influenza antigen comprising consensus hemagglutinin (HA), neuraminidase (NA), M2 ectodomain-nucleoprotein (M2e-NP), or a combination thereof, and a pharmaceutically acceptable excipient; the DNA plasmid comprising a promoter operably linked to an encoding sequence that encodes the consensus influenza antigen, and the DNA plasmid vaccine having a concentration of total DNA plasmid of 1 mg/ml or greater.
 2. The DNA plasmid vaccine of claim 1, wherein the DNA plasmid further comprises an IgG leader sequence attached to an N-terminal end of the encoding sequence and operably linked to the promoter.
 3. The DNA plasmid vaccine of claim 1, wherein the DNA plasmid further comprises a polyadenylation sequence attached to the C-terminal end of the encoding sequence.
 4. The DNA plasmid vaccine of claim 1, wherein the DNA plasmid is codon optimized.
 5. The DNA plasmid vaccine of claim 1 wherein the pharmaceutically acceptable excipient is an adjuvant.
 6. The DNA plasmid vaccine of claim 5, wherein the adjuvant is selected from the group consisting of: IL-12 and IL-15.
 7. The DNA plasmid vaccine of claim 1, wherein the pharmaceutically acceptable excipient is a transfection facilitating agent.
 8. The DNA plasmid vaccine of claim 7, wherein the transfection facilitating agent is a polyanion, polycation, or lipid.
 9. The DNA plasmid vaccine of claim 7, wherein the transfection facilitating agent is poly-L-glutamate.
 10. The DNA plasmid vaccine of claim 7, wherein the transfection facilitating agent is poly-L-glutamate at a concentration less than 6 mg/ml.
 11. The DNA plasmid vaccine of claim 1, comprising a plurality of different DNA plasmids; wherein one of the plurality of DNA plasmids comprises a sequence that encodes a consensus HA, one of the plurality of DNA plasmids comprises a sequence that encodes a consensus NA, and one of the plurality of DNA plasmids comprises a sequence that encodes a consensus M2e-NP.
 12. The DNA plasmid vaccine of claim 11, wherein the consensus HA is a consensus H1, consensus H2, consensus H3, or consensus H5.
 13. The DNA plasmid vaccine of claim 11, wherein the consensus HA is SEQ ID NO:2, SEQ ID NO:10, SEQ ID NO:12, or SEQ ID NO:14.
 14. The DNA plasmid vaccine of claim 11, wherein the consensus HA is SEQ ID NO:2.
 15. The DNA plasmid vaccine of claim 11, wherein the sequence that encodes consensus HA is SEQ ID NO:1, SEQ ID NO:9, SEQ ID NO:11 or SEQ ID NO:13.
 16. The DNA plasmid vaccine of claim 11, wherein the sequence that encodes consensus HA is SEQ ID NO:1.
 17. The DNA plasmid vaccine of claim 11, wherein the consensus NA is SEQ ID NO:4.
 18. The DNA plasmid vaccine of claim 11, wherein the sequence that encodes consensus NA is SEQ ID NO:3.
 19. The DNA plasmid vaccine of claim 11, wherein the consensus M2e-NP is SEQ ID NO:8.
 20. The DNA plasmid vaccine of claim 11, wherein the sequence that encodes consensus M2e-NP is SEQ ID NO:7.
 21. The DNA plasmid vaccine of claim 1, comprising: a DNA plasmid comprising a sequence that encodes a consensus H1, a DNA plasmid comprising a sequence that encodes a consensus H3, a DNA plasmid comprising a sequence that encodes a consensus H5, a DNA plasmid comprising a sequence that encodes a consensus NA, and a DNA plasmid comprising a sequence that encodes a consensus M2e-NP.
 22. The DNA plasmid vaccine of claim 21, wherein the consensus H1 is SEQ ID NO:2.
 23. The DNA plasmid vaccine of claim 21, wherein the sequence encoding consensus H1 is SEQ ID NO:1.
 24. The DNA plasmid vaccine of claim 21, wherein the consensus H3 is SEQ ID NO:12.
 25. The DNA plasmid vaccine of claim 21, wherein the sequence encoding consensus H3 is SEQ ID NO:11.
 26. The DNA plasmid vaccine of claim 21, wherein the consensus NA is SEQ ID NO:4.
 27. The DNA plasmid vaccine of claim 21, wherein the sequence encoding consensus NA is SEQ ID NO:3.
 28. The DNA plasmid vaccine of claim 21, wherein consensus M2e-NP is SEQ ID NO:8.
 29. The DNA plasmid vaccine of claim 21, wherein the sequence encoding consensus M2e-NP is SEQ ID NO:7.
 30. The DNA plasmid vaccine of claim 11, wherein the mammal is a primate.
 31. The DNA plasmid vaccine of claim 21, wherein the mammal is a primate.
 32. The DNA plasmid vaccine of claim 1, wherein the immune response is a humoral response.
 33. The DNA plasmid vaccine of claim 1, wherein the immune response is a cellular response.
 34. The DNA plasmid vaccine of claim 1, wherein the immune response is a combined humoral response and cellular response.
 35. A method of eliciting an immune response against a plurality of influenza virus subtypes in a mammal, comprising, delivering a DNA plasmid vaccine to tissue of the mammal, the DNA plasmid vaccine comprising a DNA plasmid capable of expressing a consensus influenza antigen in a cell of the mammal to elicit an immune response in the mammal, the consensus influenza antigen comprising consensus HA, NA, M2e-NP or a combination thereof, electroporating cells of the tissue with a pulse of energy at a constant current effective to permit entry of the DNA plasmids in the cells.
 36. The method of claim 35, wherein the delivering step comprises: injecting the DNA plasmid vaccine into intradermic, subcutaneous or muscle tissue.
 37. The method of claim 35, comprising: presetting a current that is desired to be delivered to the tissue; and electroporating cells of the tissue with a pulse of energy at a constant current that equals the preset current.
 38. The method of claim 37, wherein the electroporating step further comprises: measuring the impedance in the electroporated cells; adjusting energy level of the pulse of energy relative to the measured impedance to maintain a constant current in the electroporated cells; wherein the measuring and adjusting steps occur within a lifetime of the pulse of energy.
 39. The method of claim 37, wherein the electroporating step comprises: delivering the pulse of energy to a plurality of electrodes according to a pulse sequence pattern that delivers the pulse of energy in a decentralized pattern.
 40. A DNA plasmid capable of expressing a consensus influenza antigen in a cell of a mammal, comprising: an encoding sequence comprising consensus hemagglutinin (HA), neuraminidase (NA), M2 ectodomain-nucleo-protein (M2e-NP), or a combination thereof; a promoter operably linked to the encoding sequence that regulates expression of the consensus influenza antigen.
 41. The DNA plasmid of claim 40, wherein the DNA plasmid further comprises an IgG leader sequence attached to an N-terminal end of the encoding sequence and operably linked to the promoter.
 42. The DNA plasmid of claim 40, wherein the DNA plasmid further comprises a polyadenylation sequence attached to the C-terminal end of the encoding sequence.
 43. The DNA plasmid of claim 40, wherein the DNA plasmid is codon optimized.
 44. The DNA plasmid of claim 40, wherein the consensus HA is a consensus H1, consensus H2, consensus H3, or consensus H5.
 45. The DNA plasmid of claim 40, wherein the consensus HA is SEQ ID NO:2, SEQ ID NO:10, SEQ ID NO:12, or SEQ ID NO:14.
 46. The DNA plasmid of claim 40, wherein the consensus HA is SEQ ID NO:2.
 47. The DNA plasmid of claim 40, wherein the encoding sequence that encodes consensus HA is SEQ ID NO:1, SEQ ID NO:9, SEQ ID NO:11, or SEQ ID NO:13.
 48. The DNA plasmid of claim 40, wherein the encoding sequence that encodes consensus HA is SEQ ID NO:1.
 49. The DNA plasmid of claim 40, wherein the consensus NA is SEQ ID NO:4.
 50. The DNA plasmid of claim 40, wherein the encoding sequence that encodes consensus NA is SEQ ID NO:3.
 51. The DNA plasmid of claim 40, wherein the consensus M2e-NP is SEQ ID NO:8.
 52. The DNA plasmid of claim 40, wherein the encoding sequence that encodes consensus M2e-NP is SEQ ID NO:7.
 53. The DNA plasmid of claim 40, wherein the DNA plasmid comprises SEQ ID NO: 15, SEQ ID NO:16 or SEQ ID NO:17. 